The study of rhesus monkey social behavior has established the importance of adequate early maternal care not only for infant survival, but also for the later development of normal social, sexual,and maternal behavior. This study will examine the influence of maternal age, and other factors associated with maternal age, on the maternal behavior, infant survival, and infant social development of free-ranging rhesus monkeys. In 1974, 1975, and 1979, I collected detailed observational data on 39 free-ranging mother-infant pairs in one social group on Cayo Santiago, Puerto Rico. This study will follow-up the same individuals over a four year period--the infants now as mothers and the mothers as older mothers. Thus a larger, long-term longitudinal data base on maternal bahavior and its consequences for infants will be produced. A cross-sectional data base will also be produced for another social group. Both samples will be used to determine the extent to which maternal style is related to maternal age and to other related factors, e.g. maternal experience and numbers of older offspring in the group. Also the extent to which maternal style is carried on from mother to daughter will be assessed. These data will contribute to an understanding of whether age per se influences mothering, or whether the social circumstances surrounding older mothers are more important. This study will develop principles, hypotheses, and methods relevant to studies of human aging, maternal behavior, and child development. Many women today are deferring reproduction until their 30' and grandmothers often rear children of teenage mothers. Also the incidence of birth defects increases markedly in older mothers. Understanding the specific needs, strengths and circumstances of such mothers may help them to best cope with normal and exceptional children.